In digital communication applications, for example, Time Division Multiplexing (TDM) systems, voice data is converted from analog to digital form, and binary digits (bits) are sent over a communication network. The bits of digitized voice data are streamed serially over multiple physical communication network lines in organized formats, understandable to devices coupled to the communication network lines.
FIG. 1 illustrates an example of TDM communication data in which serial streams of digital voice data 100 are carried over a number of communication lines. Each line or stream 100 is logically divided into a sequence of frames 110, and each frame 110 includes a sequence of channels 120. Information is delivered from source to destination using bytes 102, each of which includes 8 bits 104 of data. A frame 110 contains 128 channels 120. The channels 120 are designated Channel 0, Channel 1, . . . , Channel 126, and Channel 127. A given telephone conversation will occupy one of the channels, e.g. Channel 1 of Stream No. 2. Note that each channel is allotted one byte in each frame 110 of its stream. Therefore, a conversation carried on a channel (e.g. Channel 1) is segmented into byte-sized parts that share a same stream (e.g. Stream No. 2) as 127 other conversations occupying the other 127 channels in the stream. In all, a system carrying 24 streams of data can handle (24 streams×128 conversations/stream)=3072 conversations at the same time, albeit not continuous. That is, for each streaming frame of data 110, 128 conversations are being carried (in real time to their participants) but are physically sharing the frame 110 among the 128 channels 120. In one example, the data transmission frequency is 8.192 MHz with a period of 122 nsec.
While TDM is a popular format for data transmission, it is not always possible or convenient to receive digitized voice data according to the TDM serial streaming format described above. In some cases the hardware receiving, forwarding, or processing the data streams is not adapted for the TDM format. Accordingly, for any of several reasons, it may be desirable to reformat the digital voice data streams into another useful format.